Within a turbo fan engine that utilizes a cascade type thrust reverser, there are typically a plurality of blocker doors that deploy in order to redirect engine bypass air thru a set of cascades that turn the airflow out and forward in order to reverse the direction of the thrust of the engine. This may be done to slow an aircraft after landing. Referring to FIG. 1A, a system 100 is shown. The system 100 includes a sleeve 102 that is translated or moved in, e.g., an aft direction in order to expose cascades 104 as part of the deployment of the thrust reverser. Similarly, in order to place the thrust reverser in a stowed state (e.g., during flight) the sleeve 102 is translated or moved in, e.g., a forward (FWD) direction, such that the sleeve 102 may contact or abut a thrust reverser fixed structure 106. When in the stowed state, the cascades 104 are not exposed. FIG. 3 illustrates the system 100 in the stowed state. An entirety of a nacelle is shown in FIG. 3, whereas a portion (e.g., a half) of the nacelle is shown in FIG. 1A.
The blocker doors described above are typically pivotally attached to the sleeve 102 within the thrust reverser. FIG. 1B illustrates a blocker door 108 of the system 100 hinged to the sleeve 102 near a point 110. Additionally, the door 108 is attached to the inner fixed structure 114 of the thrust reverser via a drag link 112 that retains the door 108 in position during normal flight as well as aids in the deployment of the door 108 during thrust reverse mode. During flight, the door 108 forms, in part, the outer surface of a bypass duct. The drag link 112 crosses this bypass duct in attaching to the inner fixed structure.
The drag link 112 lies within the engine airflow and generates drag losses on the engine, resulting in degraded efficiencies. Any steps and gaps around the blocker door 108 generate aerodynamic disturbances that reduce overall efficiency.
Moreover, in conventional thrust reverser systems the actuation mechanism used to drive the sleeve 102 is the same mechanism that is used to drive the blocker door 108. Accordingly, the sleeve 102 and blocker door 108 are operated at the same speed and over commonly-defined distances (also referred to as strokes).